Yamaha GW50 Owner's Manual page 25

PANEL CONTROLS AND TERMINALS
0
Two-position (Floor/Desktop) switch for setting
the display contrast for optimum
viewing.
!
For connection of an optional footswitch
(Yamaha FC5 or FC4), for controlling certain
functions and parameters as you play. (See
pages 56, 57.)
16
PANEL CONTROLS AND TERMINALS
@
For connection of an optional foot controller
(Yamaha FC7), for controlling certain functions
and parameters as you play. (See page 46.)
#
For connection of MIDI cables, when using the
GW50 with other MIDI devices. (See page
101.)